A device includes a CPU and a touch-panel display. In a first display mode, when control functions that belong to a first level are assigned to menu switches of a plurality of menus, one of the menus is displayed. In a second display mode, all the menus are displayed. A change switch is provided in a menu display selection area, and includes a plural-row mark to indicate that a plurality of menus exist at the first level. The CPU switches between the modes to display one or all menus in the menu display selection area. When a plurality of menus exist at the first level, the plural-row mark is displayed; otherwise, the plural-row mark is erased. When the menus are displayed in the second display mode, the plural-row mark is lit. When the menu is displayed in the first display mode, the plural-row mark is unlit.